Effectiveness of Alkali-Acid Treatment in Enhancement the Adsorption Capacity for Rice Straw: The Removal of Methylene Blue Dye

Table 4

Kinetic model constants and correlation coefficients for adsorption of MB dye using various adsorbents at different initial concentrations.

Adsorbents	𝐶0, (mg/L)	𝑞𝑒,exp (mg/g)	Pseudo-first-order			Pseudo-second-order			Intraparticle diffusion
			𝑘1	𝑞𝑒,cal (mg/g)	𝑅^2	𝑘^2	𝑞𝑒,cal (mg/g)	𝑅^2	𝐾id	𝐶𝑖	𝑅^2
	20	11.6	0.035	8.40	0.9642	6.66 × 10^−3	13.9	0.9923	1.43	2.02	0.9440
ARS	50	29.5	0.040	15.70	0.9799	5.77 × 10^−3	34.5	0.9987	2.67	19.1	0.9620
	80	46.4	0.033	65.70	0.9795	4.96 × 10^−4	48.8	0.9771	6.55	14.6	0.9881
	100	55.3	0.026	54.10	0.9727	1.70 × 10^−3	53.5	0.9908	8.01	3.41	0.9811
	20	11.2	0.028	6.44	0.8891	9.92 × 10^−3	12.8	0.9959	1.09	3.54	0.9173
ARS-0.5C-E	50	31.7	0.032	14.50	0.9536	6.54 × 10^−3	33.0	0.9924	1.86	17.1	0.9340
	80	49.5	0.033	29.30	0.8219	2.29 × 10^−3	54.9	0.9923	5.08	13.2	0.8512
	100	59.8	0.034	47.00	0.9518	1.28 × 10^−3	70.4	0.9969	6.35	13.1	0.9747
	20	11.8	0.020	3.96	0.6787	0.0336	12.4	0.9986	0.309	9.63	0.8864
ARS-1C-E	50	29.6	0.026	12.80	0.9028	8.47 × 10^−3	31.8	0.9984	1.63	18.5	0.9212
	80	47.9	0.038	30.40	0.9539	2.47 × 10^−3	46.1	0.9946	4.52	17.4	0.9177
	100	53.1	0.024	48.40	0.9801	4.36 × 10^−3	55.6	0.8868	5.76	10.6	0.9842
	20	11.2	0.047	2.40	0.9338	0.0581	13.4	0.9994	0.263	11.2	0.9453
ARS-0.5C	50	30.1	0.023	7.75	0.8985	0.0179	31.9	0.9997	1.08	23.4	0.8993
	80	49.8	0.026	18.5	0.8461	6.08 × 10^−3	51.3	0.9990	2.95	28.3	0.7549
	100	61.7	0.037	49.1	0.9137	1.27 × 10^−3	55.5	0.9840	8.32	2.37	0.8711
	20	11.7	0.029	3.35	0.8207	0.0326	13.9	0.9997	0.582	8.61	0.8296
ARS-1C	50	31	0.037	7.78	0.9556	0.0165	33.1	0.9998	1.21	23.7	0.8914
	80	47.3	0.038	29.9	0.8345	2.23 × 10^−3	55.2	0.9941	5.14	12.6	0.8685
	100	62.8	0.029	77.1	0.8919	8.01 × 10^−3	66.6	0.9999	2.35	47.1	0.8290
	20	10.4	0.019	8.39	0.9844	9.57 × 10^−3	11.8	0.9835	0.912	3.59	0.9853
ARS-E	50	26.1	0.018	20.2	0.8696	4.24 × 10^−3	29.0	0.9982	1.59	10.2	0.9399
	80	51.7	0.015	24.1	0.8912	0.0321	50.8	1	2.11	41.1	0.8060
	100	64	0.025	43.8	0.9465	5.83 × 10^−3	63.3	0.9997	3.63	35.3	0.8518